Greta Thunberg on Tuesday accused Israel of kidnapping her and her fellow pro-Palestinian activists in international waters, saying she declined to sign a document stating she entered the country illegally prior to being deported.

Speaking to media outlets including FRANCE 24 at the arrivals section of Paris's Charles de Gaulle airport after being deported from Israel, the Swedish activist said she and her team had broken no laws, and called for the immediate release of the activists still in Israel.

"I was very clear in my testimony that we were kidnapped on international water and brought against our will into Israel," she said.

Thunberg, 22, arrived in Paris a day after the Israeli navy prevented her and a group of fellow pro-Palestinian activists from sailing to Gaza.

Israeli forces boarded the charity vessel as it neared Gaza early on Monday, trying to break through a years-old naval blockade of the coastal enclave, and seized the 12-strong crew, including Thunberg.